D3.142 - Adherence to Inhaled Corticosteroid Therapy in Patients with Severe Asthma at a Danish Tertiary Care Centre

Inhaled corticosteroids (ICS) are essential for managing severe asthma, yet real-world adherence remains inconsistent, potentially leading to poorer disease control and increased healthcare use. Understanding adherence patterns and associated factors can guide targeted interventions. Our aim was therefore to investigate the adherence of patients at a tertiary care centre and identify possible adherence modifiers.

We conducted a retrospective, register-based cohort study of 100 patients with severe asthma treated at the Allergy Centre, Aarhus University Hospital, Denmark. Prescription redemption data from the Danish National Prescription Database were used to calculate ICS adherence over one year, expressed as a percentage of expected medication pickups based on documented daily dosages. Good adherence was defined as ≥ 80% redemption. Budesonide-equivalent daily doses were calculated to stratify treatment intensity. Associations between adherence and age, sex, % predicted FEV₁, treatment intensity, and short-acting β₂-agonist (SABA) redemption frequency were assessed using Spearman rank correlations.

Overall, 64% of patients met the ≥ 80% adherence threshold. Mean adherence was higher among males (86.7%) than females (77.8%). Adherence varied by age group, with middle-aged groups showing relatively lower adherence levels. No significant association was found between treatment intensity or SABA pickup frequency and adherence. A weak but statistically significant negative correlation was observed between % predicted FEV₁ and adherence (ρ = –0.24, p = 0.045), indicating slightly higher adherence in patients with lower lung function.

Adherence to ICS therapy in this severe asthma cohort was variable and not predicted by demographic factors or treatment intensity alone. Lower lung function demonstrated a modest association with higher adherence. These findings support the value of individualized adherence assessment and interventions in severe asthma management.